This came up on a thread on another site. (
http://videogamecritic.com/forums/viewtopic.php?f=5084&t=15864) Could some early video games have fallen into the public domain? Here's what I wrote there:
I've wondered this myself. While copyrights generally last 90 years for corporations or the life-of-the author +70 years there are exceptions.
Until the late 70's U.S. copyrights lasted 28 years. They could then be renewed for a further 28 years. After that they fell into the public domain. That's why some movies from the 40's and 50's aren't copyrighted.
Until 1980 computer programs were considered large mathematical equations; ineligible for copyright.
I think there was a period in the late 70's/early 80's where authors had to register their copyrights w/in 5 years to avoid having their works fall into the public domain. Some small publishers might not have done that, so a few obscure games could be in the public domain, but you'd need to do a ton of research to be sure.
Standard Disclaimer: I'M NOT AN ATTORNEY! THIS IS NOT LEAGLE ADVISE! I CAN'T EVEN SPELL LEAGLE! IT"S JUST SOMETHING I FIND INTERESTING! GET AN ATTORNEY WITH EXPERIENCE IN INTELLECTUAL PROPERTY LAW IF YOU WANT TO TRY ANYTHING!
I still think this is an interesting subject, and I'd like to get more thoughts on it. Any thoughts?